Urea containing grease compositions



United States Patent 3,376,223 UREA CONTAINING GREASE COMPOSITIONS Dean W. Criddle, Pleasant Hill, Califi, assignor to Chevron Research Company, San Francisco, Calif.,-a corporation of Delaware No Drawing. Filed Sept. 28, 1966, Ser. No. 582,503 3 Claims. (Cl. 25240.7)v

This invention concerns novel grease compositions having high dropping points. More particularly, thisinvention concerns novel calcium acetate containing grease compositions having high'droppin'g .points.

Numerous efforts have been made to improve greases to enhance stability, reduce separation, increase dropping point, provide desirable penetration both before and after working, as well as other desirable properties. A large number of patents directed toward improved greases have been concerned with combining calcium acetate with alkaline earth metal fatty acids having from about 12 to carbon atoms as the grease thickener. Illustrative patents are US. Patents Nos. 2,607,735, 2,842,495 and 3,186,944.

Pursuant to this invention, complex greases are obtained having desirable penetrations, both unworked and worked, and high dropping points by combining under heavy shearing conditions at elevated temperatures, calcium acetate, urea and a fatty acid of at least 14 carbon atoms in an oil medium and mixing until a grease consistency is obtained.

The calcium acetate used may be anhydrous, the monohydrate or the product formed in situ from calcium hydroxide and acetic acid. A small amount of Water may be added if anhydrous calcium acetate is employed.

Various fatty acids may be used, usually of from 14 to 20 carbon atoms, more usually of from 16 to 18 carbon atoms. The fatty acids are illustrated by palmitic acid, stearic acid, 12-hydroxystearic acid, oleic acid, linoleic acid, etc., preferably oleic acid.

The mole ratios of the materials used, on the basis of one mole of fatty acid, e.g., oleic acid, will be from 0.5 to 2 moles of calcium acetate and from 0.25 to 1.5 moles of urea.

While any oil of lubricating viscosity may be used as the medium, usually a hydrocarbonaceous lubricating oil will be used. Lubricating oils which are suitable as base oils include a wide variety of oils: mineral oils derived from petroleum, exemplified by the naphthenic base, parafiin base, asphaltic base and mixed base oils; lubricating oils derived from coal products; synthetic hydrocarbon oils; etc.

of about 275 to 450 F., more usually in the range of about 300 to 400 F.

The time in which the maximum temperature is maintained will vary, generally not in excess of one hour. The time is not critical,the mixing being stopped when the grease has the desired consistency. I

The order; of addition of the materials is. not critical.

However, thecalcium acetate will usually be added-first to the oil, followed by the urea and oleic acid. Dependent on the ratio of: ingredients, it may benecessary subsequently to have a further addition ofoil to obtain the desired consistency as the temperature is raised.

Various mixing devices-used in the grease art may be employed. These include Ganton-Maulin mill, a 3 roll mill, and a stator-rotor mill such as a Charlotte mill. It is important that the mixer provide high shear and be capable of mixing a relatively viscous medium.

Various other additives may also be included in the grease such as antirust inhibitors, corrosion inhibitors, oxidation inhibitors and extreme pressure additives.

The following examples are offered by way of illustration and not by way of limitation.

EXAMPLE I Into a Kitchen Aid pan heated on a mantle was added 800 g. of a 480 neutral oil, followed by 101.2 g. of calcium acetate. H 0 (2 moles), 17.2 g. of urea and 81.6 g. of oleic acid in that order, and the mixture stirred with an Eppenbach mixer. The temperature was slowly raised to 195 F., when the mixture started thickening and the temperature continued to be increased until 278 F. was reached. When the temperature had reached 250 R, an additional 255 g. of a 480 neutral oil was added. The product was then too thick to be mixed by the Eppenbach mixer and the flask and mantle moved to a Kitchen Aid mixer and mixing continued until 300 F. was reached.

The ASTM unworked penetration (P after 24 hours aging, the ASTM worked penetration (P after 60 strokes in the ASTM worker, and the ASTM dropping point in F. are as follows:

P =400; P =440; ASTM dropping point=645 F.

The following table indicates a number of examples which were carried out in the same manner as described in Example I. The table indicates the weights of material used, the mole ratios, the amounts of oil, the pan milling temperature, the weight percent thickener in the final grease, the penetration, both worked and unworked, and in most instances, the dropping point.

TABLE I Wt. gms. (mol ratio) Milling Penetration Dropping Weight Ex. Calcium 480 Temp., Point, Percent Acetate Urea Oleic Acid Neutral F. P P Solids Mono- Oil hydrate II .2 (2) 17. 2 (1) 81. 6 700 300 335 376 672 22 III 101 (1.99) 25 (1. 44) 82 (1) 700 300 331 365 647 23 IV- 94 (1. 5) 14 (0. 66) 100 (1 700 300 345 361 663 23 V 94 (2) 14 (1) 100 (1) 1 700 400 273 326 23 VI 101. 2 (2) 17. 2 (1) 81. 6 (1) 2 700 400 236 358 22 1 Includes 5.0 g. oxidation inhibitor.

2 Refined white oil, 113 SSU at 100 F., 40.6 SSU at 210 F.

The weight percent of solids used in the reaction will generally be from about 10 to 30 weight percent, more usually from about 12 to 25 weight percent. By solids is intended calcium acetate, urea and fatty acid.

The ingredients are generally mixed together and the temperature slowly increased to about 275 F. or higher. The maximum temperature will generally be in the range It is evident from the above results that the greases have good penetrations, both worked and unworked, and high dropping points. Moreover, the greases within this invention are found to be stable to boiling water; the greases also show excellent properties such as stability to continuous shear and compatibility with additives such as oxidation inhibitors.

usually not less than five minutesand As will be evident to those skilled in the art, various modifications on this invention can be made or followed, in the light of the foregoing disclosure and discussion, without departing from the spirit or scope of the disclosure or from the scope of the following claims.

I claim:

1. A grease composition having a hydrocarbonaceous oil of lubricating viscosity and from 10 to 30 weight percent of a grease thickener comprising a reaction product of a fatty acid of from 14 to 20 carbon atoms, calcium acetate and urea, wherein the mole ratio of fatty acid to calcium acetate is 1:1-2 and of fatty acid to urea is 1:05- 15 by shearing at a temperature at least 275 F. and not in excess of 450 F.

2. A composition according to claim 1, wherein said fatty acid is oleic acid.

3. A method of preparing a composition according to claim 1, which comprises introducing into a hydrocar- 4 y bonaceous oil of lubricating viscosity, calcium acetate, urea and a fatty acid of"fro'in 'l4'to 20 carbon atoms, wherein the mole ratio of fatty acid to calcium acetate is 111-2 and of fatty acid to urea is 1:0.51.5 to provide a weight percent of solids in the range of 10 to 30, heating while mixing at high shear to a temperature of at least 275 F. and not in excess of 450 F, until a .grease consistency is obtained.

References Cited UNITED STATES PATENTS 5/1952 Worth ct al. 252-401 Criddle 25217 

1. A GREASE COMPOSITION HAVING A HYDROCARBONACEOUS OIL OF LUBRICATING VISCOSITY AND FROM 10 TO 30 WEIGHT PERCENT OF A GREASE THICKENER COMPRISING A REACTION PRODUCT OF A FATTY ACID OF FROM 14 TO 20 CARBON ATOMS, CALCIUM ACETATE AND UREA, WHEREIN THE MOLE RATIO OF FATTY ACID TO CALCIUM ACETATE IS 1:1-2 AND OF FATTY ACID TO UREA IS 1:051.5 BY SHEARING AT TEMPERATURE AT LEAST 275*F. AND NOT IN EXCESS OF 450*F. 